Tube DACs sound wonderful if correctly designed and have a good quality valves used. I have a first hand experience with Tube DACs made on various chips such as Wolfson WM8741, Brown PCM1794, TDA1541 and ALL of them sounding very engaging that make you just seat and enjoy your music. Of course your other components need to help your DAC signal to be as least effected as possible to bring that dynamic and natural sound to your ears. When it comes to 16 Bit CD format to me TDA1541 is a King and all other Chips in Tube DAC design comes very close with a different flavour to every one of them, but the point that in the right Tube DAC design all of the major chips are capable to deliver a very musical sound.